Cooling unit for artificial refrigerating systems



VV.LI BFHDVVN Aug. 31, 1937.

COOLING UNIT FOR ARTIFICIAL REFRIGERATING SYSTEMS Filed May 11, 1954 2 Sheets-$heet 1 INVENTOR. fi zZZz'dm Z. Eran I7.

ATTORNEY.

l aw 2%? Patented Aug. 31, 1937 UNITED I STATES PATENT OFFICE William L. Brown, Detroit, Mich. Application May 11, 1934, Serial No. 725,142

9 Claims.

This invention relates to evaporators or cooling units for artificial refrigerating systems particularly of a sheet metal type adapted for use in a flooded system in which a header is required or in an expansion system.

The particular object and novel feature of the invention is to provide a cooling unit in which a conduit is formed or provided in the wall of a sheet of metal and the sheet shaped to provide the desired form of evaporator or cooling unit and a surface to receive trays.

It is also a primary object and feature of the invention to provide a new and improved cooling unit in which a tube is embedded in a thin sheet of metal and the sheet shaped to provide a plurality of side walls of a freezing chamber which sheet may be adapted for use with a header as in the flooded type of artificial refrigerating apparatus or in which the tube provides a conduit forming 20 part of the refrigerant circulating system as in the expansion type of artificial refrigerating apparatus.

More specifically, it is a feature and object of the invention to provide a sheet of metal formed 25 with a groove open to one side of the sheet and in which a tubular element is positioned to practically flush with the surface of the sheet and subsequent to the positioning of the tube therein, brazing the same in place and then forming the 30 sheet to provide an evaporator or cooling unit of the desired shape.

Also an important feature of this invention consists in the character of construction of the cooling unit in which a sheet of metal is formed to 5 provide a series of parallel grooves in each of which a tube is inserted to a position practically flush with the surface of the sheet, the unit being formed by bending the sheet to bring the opposite ends of the grooves and tubes together in 40 an offset relation so that the end of the tube of one groove is aligned with the tube of the next in succession thereby providing a continuous spiral coil.

It is also an object and feature of the inven- 45 tion to provide a cooling unit formed of a sheet of metal having parallel grooves and tubes therein and a header to which at least one end of the tubes are introduced and adapted for use in a flooded system.

These and other objects and several novel features of the invention are hereinafter more fully described and claimed, and the preferred form of a structure embodying my invention is shown in the accompanying drawings in which- Fig. lis a perspective view showing the sheet shaped and secured to a header as in the flooded type of refrigerating apparatus.

Fig. 2 is a cross section taken on line 22 of Fig. 1 showing one manner of securing the tubes to the header.

Fig. 3 is a cross section of a portion of the sheet including a tube taken on line 33 of Fig. 1.

Fig. 4 shows a. portion of a grooved sheet and a split tube in section prior to assembly.

Fig. 5 shows a split tube in assembled relation with the sheet and prior to the final step of formation in which the tube is finally secured in place as in Fig. 3.

Fig. 6 is a View similar to Fig. 4 showing the use of a seamless tube for association with the roove in the sheet.

Fig. 7 is a detail showing the manner of closing the end of the tube in the sheet.

Fig. 8 is a cooling unit for the expansion type of refrigerating apparatus in which the grooved sheet having the tubes therein has been formed in a rectangular shape with the ends of each tube in axial alignment.

Fig. 9 is a similar view showing the formed unit with the tubes offset by movement of one edge of the sheet relative to the other in a direction indicated by the arrow in Fig. 8 whereby a conj tinuous coil is obtained.

Fig. 10 is an end view of the structure as applied to a header.

In the formation of a cooling unit such as shown in Fig. 1 for instance, a sheet of metal I is formed with a series of parallel grooves 2 having the full width of opening at the face of the sheet as shown in Fig. 4 and in these parallel grooves may be laid a split tube 3 with the split face to be seated in the bottom of the groove as indicated in Fig. 5 in conjunction with a brazing compound. Subsequent to positioning the tube 3 in the groove as shown in Fig. 5, the grooved portion of the sheet is forced about the tube to the position shown in Fig. 3 which applies pressure to the tube closing the open seam 4. Subsequent to the provision of the sheet with the several tubes, as indicated in Fig. 1, the sheet and tubes are submitted to a heat at brazing temperature. The groove of the tubes or both may have the brazing compound applied thereto so that when subjecting the same to heat as in an oven, the tube is fixed in place and the seam sealed.

Obviously, the invention is not confined to use of the tube having the open side 4 although such form is probably the cheaper form. It is obvious that a seamless tube, such as suggested in Fig. 6, may be introduced into the groove in which the opposite end of the tube to a position as indicated in Fig. 3 will sufficiently secure it in place.

In either form of tube, one end of the completed sheet may be pressed fiat as indicated at 5 in Fig. l which compresses the end of the tube and the portion of the sheet forming the groove and in the brazing process to which the sheet is finally submitted, this end of the sheet and tube may be completely sealed. At the opposite end of the sheet the tubes may project slightly and to these tube ends is secured the header formed of the lower half 6 and the upper half I, the edges of which are inturned over one another as indicated at 8. However, before the upper half 1 of the header is in place the lower half 6, which has apertures to receive the tube ends has these ends inserted therein and inturned over the wall as indicated at 9 in Fig. 2. Preferably the tube is provided with an outstanding circumferential rib In so that, in swaging out the open end of the tube as shown in Fig. 2, the metal of the shell 6 lies snugly in between the' rib l and the flange 9 of the tube. As this lower half 6 of the header is open at this time the tubes are readily swaged out and thereafter the upper half I of the header is positioned thereon and the whole unit submitted to brazing heat. In this structure the header of course contains the refrigerant and the tubes are full of refrigerant and this may be introduced into a compartment of a refrigerator and the different portions of the Z-form shown in Fig. 1 provide chambers in which material or trays may be placed for the quick freezing effect. It will be noted that as evaporation of the refrigerant in the tubes takes place the gas will pass up these tubes to the header and thus secure the necessary circulation.

It is not necessary that the sheet and embedded tubes to be folded to the Z shape as shown in Fig. 1 or even provided with a header which is not required in the expansion type of refrigerating system. On the contrary, the sheet, after the tubes have been placed therein, may be brought with the ends to alignment as indicated in Fig. 8 and forming a freezing chamber of rectangular form in cross section. In order that the proper circulation of refrigerant may take place, one end I I of the sheet is moved along the longitudinal axis of the chamber to the right of Fig. 8 to bring the tubes to the position shown in Fig. 9 and thus each tube has one end brought to alignment with an end of the succeeding tube and the assembled tubes form a continuous coil through which the refrigerant will pass. It is to be noted than an end l2 of one tube may provide an inlet and an end l3 of the last tube of the series may provide an outlet. In this arrangement the tubes could be provided with a projecting end as indicated at Hi to be introduced into the groove of the the sheet and there welded or brazed in place by submitting the seams to a brazing operation. In the form of the sheet shown in Fig. 10 the tubes at the end l5 may be introduced into a header H5 at a comparatively low point and the tubes at the opposite end I! opening to the header at a higher point. By having the end l5 at a lower point the said end is always below the liquid level in the header l6 while the end l1 may be at or somewhat above the liquid level. This provides a common form of evaporator for use in the flooded type of refrigerating apparatus.

In each of the forms shown in Figs. 1, 8, 9 and 10, a sheet of metal is first provided with a series of parallel grooves and the tubes, either a split or a seamless tube, inserted therein and brazed in place as before described. The invention is not limited to the form of sheet hereinbefore described as other forms of sheet like material may be utilized without departing from the spirit and scope of the invention herein disclosed.

The invention resides in the manner of formation of the sheet with an embedded tube. By this arrangement there is less metal utilized than in the commonly known double sheet type of cooler, such for instance as is shown in the patent to Booth, Reissue 18,182 of September 6; 1931. In any such type of cooler there is an inner and and thus considerable more weight is required than with the single sheet of my invention.

Also, by the insertion of the tube, I avoid the necessity of welding the sheet between the grooves or ribs in the form shown in Figs. 1, 8, 9 and 10 and further provide a structure in which leakage of the refrigerant is avoided. Thus expense of manufacture is reduced to a minimum, not only due to there being less metal utilized but also due to the fact that the brazing or welding in my structure is performed by submission of the whole unit to the required brazing or welding temperature. In my structure the tube inserted in the groove of the sheet and with a brazing or like material lying in the groove and between the tube and the groove, the tube wall is in intimate metal association with the wall of the groove and thus the sheet becomes an effective dissipator of cold and highly efficient in transferring the heat to the refrigerant. The invention therefore resides in the formation of a sheet 1 with tubing secured in the groove formed to extend to one side of the sheet and the particular shape of the unit to be manufactured from the sheet is not material as any desired shape can be made, several of which are here shown.

It is evident from the foregoing descriptionthat the various objects of the invention are attained by the manner of construction of the sheet with the tube embedded therein and that the invention not only resides in the article formed by the tube embedded sheet but also in the method by which the tube is made a component part of the sheet to provide a wall of a freezing or cooling chamber.

Having thus briefly described my invention, its utility and mode of operation, what I claim and desire to secure by Letters Patent of the United States is- 1. A sheet metal cooling unit for a refrigerating system comprising a sheet of metal formed witha groove extending longitudinally thereof, a cylindrical tube inserted in the groove, the depth of the groove being greater than the diameter of the tube and the sheet having a portion wrapped practically completely about the circumference of the tube and providing a sheet with a practically fiat face with the tube disposed practically wholly on the opposite side the sheet and tube being bent to form a hollow chamber with the flat face of the sheet forming the walls of the chamber.

2. A sheet metal cooling element for a refrigerating system comprising a shell of sheet metal formed with a series of parallel grooves opening through one side thereof and extending from the other side thereof, a tube inserted in each of the grooves, the tubes extending from one end of the grooves, a header to which the extending end of the tube is secured and to which the tubes open,

6. A cooling unit for an artificial refrigerating the tubes at the opposite end of the sheet being sealed to atmosphere.

3. A sheet metal cooling element for refrigerating systems comprising a shell formed of a 5 sheet of metal having a series of parallel grooves formed therein and extending from one side of the sheet, a tube inserted in each of the grooves, the shell being shaped to bring the two ends of the sheet together to form an interior chamber with the ribs forming the grooves on the outside thereof, the ends of the successive tubes being offset to align an end of each tube with an end of the next tube of the series to form a continuous conduit, the open endof the tube at one end of the series providing an inlet and the tube at the opposite end of the series having an open end providing an outlet and adapting the same for connection in a refrigerant circulating system.

4. A cooling unit for an artificial refrigerating system comprising a sheet of metal formed with a series of parallel grooves open through one face thereof, a tube in each of the grooves, the grooves being of a depth substantially equal to the external diameter of the tube and the walls of the groove being impressed at the point of unition with the sheet to secure the tube in place therein, said sheet and the embedded tubes being shaped to provide a chamber of the desired form and having a comparatively smooth wall with the ribs formed by the grooves on the exterior thereof, a header consisting of a half shell to which one end of the sheet and tubes are secured with the tubes opening through the=half shell near the bottom and the other end being united therewith and the 36 tubes opening thereto at a point above the first end, a second half shell secured insealed relation to the first half and with the first half forming a header, the said tubes forming passageways for liquid refrigerant to pass therethrough from the 40 lower side of the header and the expanded gases returning to the header from the opposite .end.

5. A coolingunit for an artificial refrigerating system comprising a sheet of metal formed with a plurality of parallel grooves opening through one face thereof, a tube in each of the grooves, a. header to which at least one end of the tubes is in communication and the other end of the tubes being closed to atmosphere, the said sheet with the embedded tubes having the shape of a 2 providing separate chambers for material to be chilled and in which at least three sides of the material are exposed to influence of the lowered temperature of the sheet and tubes.

apparatus comprising a sheet of metal formed with a plurality of grooves opening through one face thereof and forming ribs on the opposite face, a tube brazed in position in each of the grooves, the sheet and tubes being bent to form a four-sided freezing chamber, the ends of the sheet and tubes being ofiset whereby an end of each tube is aligned with an end of the next tube of the series whereby a continuous coil is secured.

7. An evaporator for an artificial refrigerating apparatus comprising a sheet of metal having a series of .tubes embedded therein in parallel relation, the ends of the tubes opening through the respective ends of the grooves and the sheet with r the tubes embedded therein being shaped to provide a plurality of sides of a freezing chamber, said tubes'each having an end secured to the end of a tube of the next of the series providing a continuous conduit for refrigerant.

8. In a cooling unit for an artificial refrigerating system, a comparativelythin sheet of metal having a groove opening through one side and forming a rib on the opposite side, a tube positioned in the groove, the depth of the groove being approximately equal to the external diameter of the tube, said tube being in the form of 9. rolled sheet having spaced edges providing an open seam and disposed in the groove with the seam at the bottom thereof, the edges ofthe sheet at the throat of the groove being spaced apart a. distance less than the diameter of the tube and the wall of the groove being in pressure contact with the wall of the tube providing surface contact between the tube and the said wall of the groove said sheet being shaped to provide a freezing chamber in which the ribs formedby thegroove are onthe H exterior face thereof.

9. An evaporator comprising a casing formed of a single sheet of metal and providing at least three sides of a freezing chamber, a tube embedded in the sheet to nearly its full diameter and providing a throat of less width'than the diameter of the tube and the tube except at said throat being in surface contact with the wall of the groove, said sheet and embedded tube providing a structure with a substantially flat face on ,one side with the tube disposed practically wholly on the opposite side, the tube providing a sealed conduit for a refrigerant.

WILLIAM L. BROWN. 

